The present invention relates generally to the field of digital content delivery, and more particularly to systems for broadcasting and receiving content in parallel to allow for a switchover between broadcast reception and two-way digital channel reception.
Rapid and considerable improvements have been made in recent years in the field of digital content delivery. A conventional mechanism for broadcast delivery of content included television broadcast in which signals are transmitted from broadcast towers and received on television receivers, set top boxes, and so forth. Similar systems have been put in place for cable and satellite transmission. Content transmitted by these mechanisms may include conventional television programming, movies, audio, video, multimedia and other entertainment content, business and surveillance content, and so forth. Increasingly, however, there is a desire to further advance the field through the ability to transmit and receive such content on mobile devices, such as mobile televisions, smart telephones, handheld devices, and so forth.
More recent developments in the mobile broadcast area have included standards developed and under development by such bodies as the Advanced Television Systems Committee (ATSC). The standards currently include mobile digital television (MDTV) standards designed to allow for devices to be truly mobile while receiving television broadcasts. In North America, such standards are being advanced still further by the establishment of ATSC mobile/handheld (ATSC-M/H) standards for handheld transportable devices. Other parallel standards are being established in other areas of the world.
Many such devices can and do receive streams of digital content by channels other than broadcast channels, however. In particular, many smart phones and mobile devices today communicate readily over the Internet to receive images and web pages, streaming audio, streaming video, multimedia, content, podcast, and so forth. In general, the ability to transmit content via broadcast channels is greatly preferred in many contexts. For example, standard broadcast schedules can be developed and content may be broadcast through established infrastructure with little or no change. Where desired, similar broadcasts can be transmitted to conventional receivers (stationary televisions) and to mobile devices. Moreover, Internet content, while extremely flexible in terms of time shifting and responsiveness to user requests, are often limited in bandwidth, with users often paying a premium for the reception of on-demand content from Internet sources. Current business models often channel these costs through the telephone or Internet service provider.
Although broadcast mechanisms may be preferred, they are often plagued by the unreliability of quality transmission, reception and playback. Such problems are often causes by inconsistent, shifting transmission quality, particularly due to atmospheric interferences, particularly for mobile devices that are actually moving during reception. Although advances will certainly occur, particularly through the further development of MDTV and similar standards, it is anticipated that for the foreseeable future difficulties will persist in the ability to reliably receive and playback digital content on mobile devices that is received by broadcast channels.
Moreover, certain broadcast techniques have been developed that are capable of handling some degradation in signal quality. One such technique, sometimes referred to as “staggercasting”, allows for multiple streams of the same content to be broadcast that are staggered in time (e.g., time delayed with respect to one another), effectively accumulating buffer time. However, the same or similar channels are used in such approaches, ultimately resulting in increased the use of the available broadcast bandwidth, with little real resolution of the ability to receive content in an uninterrupted manner in the event of deteriorating signal quality.
There is a need, therefore, for improved mechanisms allowing users to make use of broadcast channels where available for receiving and playing back content on mobile devices, while relying upon the robust nature of Internet transmissions where the broadcast channels are lacking.